Regulating valve for hydraulic cylinders

ABSTRACT

A valve apparatus for controlling the retraction movement of a hydraulic cylinder has a valve closure connected to a piston by a piston rod. The hydraulic cylinder communicates intermediate the piston and the closure. A comparatively strong spring urges the piston and closure toward the valve closed position, while a relatively weak spring urges the piston and closure toward the unseated position. An electric valve operator disables the relatively strong spring allowing the relatively weak spring to move the closure off its seat. A flow control orifice is downstream of the valve seat whereby pressure is built up downstream of the closure to cause a back pressure on the closure so that the closure serves as a pressure regulator.

United States Patent [1 1 Clarke et al.

[4 1 Sept. 2, 1975 REGULATING VALVE FOR HYDRAULIC CYLINDERS [76] Inventors: Dudley S. Clarke, 1140 S.

Washtenaw Ave., Chicago, 111. 60612; Jack J. Camera, 1252 N. Pine, Chicago, 111. 60651 [22] Filed: Nov. 8, 1968 [21] Appl. No.: 774,440

[52] US. Cl. 91/418; 91/459; 251/68 [51] Int. Cl....F15b 11/08; F15b 11/044; F16k 31/00 [58] Field of Search 91/418, 459; 251/66, 68, 251/73, 74

[56] References Cited UNITED STATES PATENTS 2,258,811 10/1941 Ray 251/68 X 2,688,460 9/1954 Borgerd..... 3,164,359 l/1965 Dyer et al. 3,211,414 10/1965 Webb 3,330,110 7/1967 Sprayberry 91/418 X 3,376,792 4/1968 Clarke et al. 91/443 Primary ExaminerMartin P. Schwadron Assistant Examinerlrwin C. Cohen [5 7] ABSTRACT A valve apparatus for controlling the retraction movement of a hydraulic cylinder has a valve closure connected to a piston by a piston rod. The hydraulic cylinder communicates intermediate the piston and the 6 Claims, 2 Drawing Figures Fl urea 29 I4 I lv-zs la I LENOID VALVE FLTER 28 1 R as RVO R 30 27 2 PATENTEDSEP 2197s SHEET 2 [If 2 REGULATING VALVE FOR HYDRAULIC CYLINDERS SUMMARY OF THE INVENTION The present invention relates to a simple and efficient control valve apparatus for smoothly controlling the down stroke of a loaded hydraulic cylinder.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a hydraulic system embodying the present invention; and

FIG. 2 is atransverse cross-section of an embodiment of the valve apparatus.

DESCRIPTION OF THE SPECIFIC EMBODIMENT Although the following disclosure offered for public dissemination upon the grant of a patent is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may latter disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

The present invention is an improvement on the valve apparatus disclosed and claimed in US. Pat. No. 3,376,792. It is for the same general purpose, namely controlling the retraction movement of a hydraulic cylinder l filled with hydraulic fluid and loaded as indicated by weight 11. The hydraulic fluid is held in a reservoir 12. A pump 13 communicates with reservoir 12 by means of a conduit 14. A filter 21 is interposed in conduit 14 between reservoir 12 and pump 13. A conduit 15 connects the pressure side of pump 13 with check valves 17 and 18. Check valve 18 serves as a high pressure relief and will discharge any excess pressure in line 15 back into reservoir 12 through conduit 19.

A conduit 20 connects check valve 17 with filter 22 and cylinder 10. A conduit 25 connects filter 22 and the control valve 26. A conduit 27 having an orifice 28 therein connects valve 26 with reservoir 12. Valve 26 is operated by a solenoid 29. The solenoid is energized from a suitable source of electricity when switch 30 is closed. Pump 13 is driven by electric motor 31. Motor 31 is energized from a suitable source of electricity when switch 32 is closed.

To raise the load 11, switch 32 is closed whereupon pump 13 delivers hydraulic fluid to cylinder 10, valve 26 being closed. When the raising of load 11 is to be stopped switch 32 is opened. To lower load 11, switch 30 is closed energizing solenoid 29 and opening valve 26 to allow the hydraulic fluid from cylinder 10, which fluid is under pressure, to return through conduit 27 to reservoir 12.

The valve apparatus of the present invention is intended to be a packaged unit of the general configuration of that in US. Pat. No. 3,376,792, which, for example, can be mounted on a side of reservoir 12. It has the advantages that it gives a smooth descending movement to load 11 without undesirable bounce and jiggle; it is comparatively simple and inexpensive to manufacture; and it has a comparatively long service life without the necessity for repairs. Should repairs be necessary, these can easily be made by the substitution of components in the valve body so that the apparatus is not out of service for an appreciable period of time. It also canemploy a comparatively inexpensive operating solenoid without the danger of burning out the solenoid by temporary malfunctions.

Referring to FIG. 2, the main valve body 35 is generally in the form of a block which, in addition to the valve apparatus illustrated and described, would include the check valves and filters discussed in connection with FIG. 1. These are not further illustrated in FIG. 2 inasmuch as the manner in which they would be incorporated is generally' disclos'ed in US. Pat. No. 3 376,792. The body 35 has a bore 36 extending therethrough. Within this bore is a cylindrical regulator body 37. Regulator'body 37 has an opening 38 which communicates with and forms a part of conduit 25. In the actual apparatus the opening 38 is in the portion of body 37 above the paper of FIG. 2. But this is merely a matter of placement of other components in body 35 and for convenience of illustration the opening has been moved 180 about the axis of body 38.

At each side of opening 38 are O-rings 39 forming a seal between the internal walls 41 defining bore 36 and the exterior 42 of regulator body 37. A set screw 43 threaded into main body 35 engages regulator body 37 to hold the regulator body in place in the main valve body. Removal of the set screw 43 permits removal, and replacement of the entire valve assembly from bore 36.

One end of bore 36 is closed by a plug 45 threaded into body 35. Extending laterally from bore 36 is a plug 46 having an internal opening defining orifice 28. Plug 46 is interchangeable and to this end it is threaded into body 35 and has a slot 47 in the outer face thereof so that it can be engaged by a spanner wrench or the like. Between regulator body 37 and plug 45 the bore 36 forms a chamber 48 which, for the purposes of convenience, will be referred to as the reservoir chamber since it communicates with reservoir 12 through conduit 27. The adjacent end of regulator body 37 forms a valve seat 49 which cooperates with a valve closure 50. A valve stem 52 connects closure and a piston 53, both being received in a cylindrical opening 54 in regulator body 37. An O-ring 55 forms a seal with the internal wall of the regulator body. .The portion of opening 54 between the inner end 56 of closure 50 and the adjacent end 57 of piston 53 defines a chamber which, for the purposes of convenience, will be referred to as the cylinder chamber 58 since it is that portion of the valve which communicates with the cylinder 10 through opening 38, conduit 25, filter 22, etc.

A rod 60 has an end 61 secured to piston 53 by being threaded into the piston. The other end of rod 60 has a head 62 serving as a stop. Encircling rod 60 are washers 63 and 64, both of which are slideable with respect to the rod. A comparatively heavy spring 66 encircles rod 60 and is in compression between washers 63 and 64. This spring holds washer 64 firmly against the end 67 of regulator body 37. Since regulator body 37 is held in place by set screw 43, wash-er 64 may be regarded,

for all practical .purposes, as forming fixed abutments on the opposite. faces thereof. A comparatively light spring 68 is in compression between washer 6 4 and end 69 of piston 53. By way of illustrating the comparative strength of springs 66 and 68., spring 66 exerts 19.5 pounds and spring 68 exerts 7.5 pounds with the assembly in the position illustrated in FIG. 2.

.At the left end of bore 36 is a plunger 71 which has an internal opening 72 defined by an annulus 73 of the plunger. Solenoid 29 is secured to body 35 by cap screw 74. The solenoid has a push rod 75 which is moved to the right by the armature of the solenoid when the solenoid coilis energized. The plunger 71 could be operated by other devices, evenmanually, by which a small force can be exerted to the right on the plunger.

With the valve apparatus in the position illustrated in FIG. 2, the pressure of the hydraulic fluid in cylinder is applied to cylinder chamber 58. For all practical purposes, the exposed areas 56 and 57 of closure 50 and piston 53 respectively are equal (with the closure seated) so that the effect of the pressure in chamber 58 is evenly distributed, i.e..the forces tending to move valve stem 52 in opposite directions are equal. Thus even though thefluid pressure is relatively high, spring 66 has no difficulty in holding the valve closure 56 against seat 49. For all practical purposes, there is no pressure in reservoir chamber 48 since that chamber opens into the unpressurized reservoir 12.

Assuming that it is now desired to lower load 11 (pump 13 being stopped), the solenoid 29 is energized so -that push rod 75 moves plunger 71 to the right in FIG. 2. This force is not exerted on rod 60, but rather annulus 73 bears against washer 63 so that the force is used to move washer 63 to the right with spring 66 being further compressed. Washer 64 is, of course, immovable, being butted against regulator body 37. Moving washer 63 to the right away from head 62 disables spring 66 so that it is no longer exerting any force on head'62 of rod 60 and, in effect, causes a space to occur between washer 63 and head 62. In actuality no such space of any significance will occur since piston 53, rod 60 and head 62 are now free to move to the right under the urging of spring 68 (washer 64 being held immovable'by spring 66 and regulator body 37).

The movement of piston 53 to the right moves closure 50 a corresponding distance away from its seat 49. As soon as this movement commences, hydraulic fluid flows through the passageway defined by opening 38, chamber 58, chamber 48 and orifice 28 (in effect a flow from conduit through conduit 27 to reservoir 12). The orifice 28 will permit only a limited flow so that a back pressure will develop in chamber 48. Since the end 76 of closure 50 has a comparatively large area and, to some extent, the pressures on ends 56 and 57 are balanced out, the back pressure in the passageway will have a resultant force on the assembly tending to move closure 50 toward its seat in opposition to the urging ofspring 68. Thus the assembly now acts as a pressure regulating valve. Closure 50 will move gradually away from its seat (as plunger 71 is moved to the right) until an equilibrium is reached at which this resultant of the hydraulic forces'applied will balance out the force applied by spring 68. By changing the size of orifice 28 one can change the rate of flow through the valve apparatus, other factors remaining constant. If solenoid 29 is at any time deenergized, spring 66 is again rendered effective. The additional force applied to the assemblage by spring 66 is more than enough to drive the closure 50 to the left, closing the valve and stopping the descent of load 11.

It takes only a relatively small stroke of plunger 1 l to convert the valve apparatus from an on-off valve to a pressure regulating valve. In an actual embodiment this is only a travel of about one-sixteenth of an inch with solenoid 29 exerting a relatively small pressure on plunger 71. A sleeve 77 is inserted merely as a precaution against an occurrence which would tend to move the closure 50 too far from its seat. The sleeve thus forms a safety stop to prevent an over-travel of washer 63 to the right in FIG. 2.

We claim:

1. In a control valve apparatus for use in controlling the movement of a loaded hydraulic cylinder containing hydraulic fluid under pressure which fluid is to be returned to a reservoir through the apparatus to effect operation of the cylinder, the improvement in said apparatus comprising:

means including a regulator body having a passageway therethrough, said body defining a valve seat encircling a portion of said passageway, said pas sageway at one side of said seat defining a cylinder chamber and at the other side of said seat defining a reservoir chamber; first conduit means communicating with said cylinder chamber for connecting said cylinder chamber to said cylinder; second conduit means communicating with said reservoir chamber for connecting said reservoir chamber to said reservoir, said second conduit means including orifice means to control the rate of flow of hydraulic fluid to said reservoir; regulating valve means having a valve closure and a valve stem, said closure being against said seat with the stem extending from the closure into said cylinder chamber whereby the exposed area of the closure on the cylinder chamber side of the closure is less than the exposed area on the other side of the closure, piston means in the cylinder chamber and secured to the stem at a spaced distance from the closure whereby the fluid under pressure from the cylinder acts on the piston means to exert a force in one direction on the stem and acts on said cylinder chamber side of the closure to exert a force in the other direction on the stem, first spring means operatively associated with said closure to exert a first force on said closure for urging said closure away from said seat, and second spring means operatively associated with said closure to exert a second force on said closure for urging said closure into sealing contact with said seat, said spring means being such that the force applied to said closure by said second spring means is greater than the force applied to the closure by said first spring means; and actuating means operatively associated with said second spring means to disable said second spring from exerting said second force on said closure. 2. In an apparatus as set forth in claim 1, wherein said piston means has an end in said cylinder chamber and an end opposite thereto, and said regulating valve means includes a rod secured to said opposite end of said piston means, first abutment means at a spaced distance from said opposite end and restrained against movement in the direction toward said opposite end, said first spring means being in compression between said opposite end and said first abutment means, a stop on said rod a spaced distance in the opposite of said direction from said first abutment means, and second abutment means encircling said rod adjacent said stop and movable longitudinally of said rod, said second abutment means being in contact with said stop. said second spring means being in compression between the two abutment means to urge said rod, piston means and closure towards the valve closed position, said actuating means being positioned to contact said second abutment means and to move said second abutment means towards the first abutment means to further compress said second spring means to release said urging of the second spring means from said rod, piston means and closure.

3. In an apparatus as set forth in claim 2, wherein said apparatus includes a main valve body having an internal cylindricalwall forming a first cylindrical bore extending therethrough and having two ends, said regulator body being in said bore intermediate the ends thereof, means releasably fixing said regulator body in said bore, sealing means between the exterior of said regulating body and said wall, said seat being at one end of the regulator body and said first abutment means being seated against the other end of the regulator body, said one end of the regulator body being spaced from one end of the bore to define said reservoir chamber therebetween, said actuating means being at least partially in said bore at said other end of the bore and having an annular portion bearing against said second abutment means with said stop being within said annular portion.

4. In an apparatus as set forth in claim 3, including means plugging said one end of said bore, said orifice means being removably mounted in said main body and positioned transversely of said bore and in communication with said bore.

5. In an apparatus as set forth in claim 3, including a movement limiting sleeve between the two abutment means and shorter in length than the distance between the two abutment means.

6. In an apparatus as set forth in claim 1, wherein said apparatus includes a main valve body having an internal cylindrical wall forming a first cylindrical bore extending therethrough and having two ends, said regulator body being in said bore intermediate the ends thereof, means releasably fixing said regulator body in said bore, sealing means between the exterior of said regulator body and said wall, said seat being at one end of the regulator body, said one end of the regulator body being spaced from one end of the bore to define said reservoir chamber therebetween, said other end of the regulator body being spaced from the other end of the bore, said actuating means being at least partially in said bore at said other end of the bore and having an annular portion bearing against said other end of the regulator body. 

1. In a control valve apparatus for use in controlling the movement of a loaded hydraulic cylinder containing hydraulic fluid under pressure which fluid is to be returned to a reservoir through the apparatus to effect operation of the cylinder, the improvement in said apparatus comprising: means including a regulator body having a passageway therethrough, said body defining a valve seat encircling a portion of said passageway, said passageway at one side of said seat defining a cylinder chamber and at the other side of said seat defining a reservoir chamber; first conduit means communicating with said cylinder chamber for connecting said cylinder chamber to said cylinder; second conduit means communicating with said reservoir chamber for connecting said reservoir chamber to said reservoir, said second conduit means including orifice means to control the rate of flow of hydraulic fluid to said reservoir; regulating valve means having a valve closure and a valve stem, said closure being against said seat with the stem extending from the closure into said cylinder chamber whereby the exposed area of the closure on the cylinder chamber side of the closure is less than the exposed area on the other side of the closure, piston means in the cylinder chamber and secured to the stem at a spaced distance from the closure whereby the fluid under pressure from the cylinder acts on the piston means to exert a force in one direction on the stem and acts on said cylinder chamber side of the closure to exert a force in the other direction on the stem, first spring means operatively associated with said closure to exert a first force on said closure for urging said closure away from said seat, and second spring means operatively associated with said closure to exert a second force on said closure for urging said closure into sealing contact with said seat, said spring means being such that the force applied to said closure by said second spring means is greater than the force applied to the closure by said first spring means; and actuating means operatively associated with said second spring means to disable said second spring from exerting said second force on said closure.
 2. In an apparatus as set forth in claim 1, wherein said piston means has an end in said cylinder chamber and an end opposite thereto, and said regulating valve means includes a rod secured to said opposite end of said piston means, first abutment means at a spaced distance from said opposite end and restrained against movement in the direction toward said opposite end, said first spring means being in compression between said opposite end and said first abutment means, a stop on said rod a spaced distance in the opposite of said direction from said first abutment means, and second abutment means encircling said rod adjacent said stop and movable longitudinally of said rod, said second abutment means being in contact with said stop, said second spring means being in compression between the two abutment means to urge said rod, piston means and closure towards the valve closed position, said actuating means being positioned to contact said second abutment means and to move said second abutment means towards the first abutment means to further compress said second spring means to release said urging of the second spring means from said rod, piston means and closure.
 3. In an apparatus as set forth in claim 2, wherein said apparatus includes a main valve body having an internal cylindrical wall forming a first cylindrical bore extending therethrough and having two ends, said regulator body being in said bore intermediate the ends thereof, means releasably fixing said regulator body in said bore, sealing means between the exterior of said regulating body and said wall, said seat being at one end of the regulator body and said first abutment means being seated against the other end of the regulator body, said one end of the regulator body being spaced froM one end of the bore to define said reservoir chamber therebetween, said actuating means being at least partially in said bore at said other end of the bore and having an annular portion bearing against said second abutment means with said stop being within said annular portion.
 4. In an apparatus as set forth in claim 3, including means plugging said one end of said bore, said orifice means being removably mounted in said main body and positioned transversely of said bore and in communication with said bore.
 5. In an apparatus as set forth in claim 3, including a movement limiting sleeve between the two abutment means and shorter in length than the distance between the two abutment means.
 6. In an apparatus as set forth in claim 1, wherein said apparatus includes a main valve body having an internal cylindrical wall forming a first cylindrical bore extending therethrough and having two ends, said regulator body being in said bore intermediate the ends thereof, means releasably fixing said regulator body in said bore, sealing means between the exterior of said regulator body and said wall, said seat being at one end of the regulator body, said one end of the regulator body being spaced from one end of the bore to define said reservoir chamber therebetween, said other end of the regulator body being spaced from the other end of the bore, said actuating means being at least partially in said bore at said other end of the bore and having an annular portion bearing against said other end of the regulator body. 